초록 ▼

A magnetically enhanced plasma is produced with a permanent magnet assembly adjacent to a radio frequency (RF) biased wafer support electrode in a vacuum processing chamber of a semiconductor wafer processing apparatus. An annular peripheral region is provided on the wafer support around the perimet

A magnetically enhanced plasma is produced with a permanent magnet assembly adjacent to a radio frequency (RF) biased wafer support electrode in a vacuum processing chamber of a semiconductor wafer processing apparatus. An annular peripheral region is provided on the wafer support around the perimeter of the wafer being processed. A magnet arrangement using a plurality of magnet rings forms a magnetic tunnel over the peripheral region at which the plasma is generated away from the wafer. The magnetic field has components parallel to the substrate support surface over the annular peripheral region but which are perpendicular to the surface at the wafer. Preferably, the magnetic field has a flat portion parallel to the support surface in the peripheral region. Plasma propagates by diffusion from the peripheral region across the wafer surface. The magnets can be manipulated to optimize plasma uniformity adjacent the substrate being processed.

대표청구항 ▼

The invention claimed is: 1. A plasma processing apparatus comprising: a vacuum chamber; a wafer support within the chamber having a central wafer supporting surface lying in a plane and an annular peripheral surface surrounding the central wafer supporting surface and lying in the plane; an RF ge

The invention claimed is: 1. A plasma processing apparatus comprising: a vacuum chamber; a wafer support within the chamber having a central wafer supporting surface lying in a plane and an annular peripheral surface surrounding the central wafer supporting surface and lying in the plane; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two poles configured to form an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly being configured to produce a resultant magnetic field over the surfaces of the wafer support that includes resultant magnetic flux lines generally parallel to the annular peripheral surface in the region thereof and generally isolated from the central wafer supporting surface in the region thereof; the annular permanent magnet assembly including at least two annular magnet rings including an outer annular magnet ring and a second annular magnet ring located within the outer annular magnet ring, the rings each having north and south magnetic poles, the second magnet ring being either an inner annular magnet ring or an intermediate annular magnet ring located between the outer annular magnet ring and an inner annular magnet ring; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first pole thereof facing the annular peripheral surface of the wafer support; and the second annular magnet ring having a polar axis parallel to the surfaces of the wafer support and having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing away from the central wafer supporting surface. 2. The apparatus of claim 1 wherein: the annular permanent magnet assembly is located behind the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly through and over the surfaces of the support. 3. The apparatus of claim 1 wherein: the annular permanent magnet assembly is located opposite and is spaced from the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly toward and through the surfaces of the support. 4. A plasma processing apparatus comprising: a vacuum chamber; a wafer support within the chamber having a central wafer supporting surface and an annular peripheral surface surrounding the central wafer supporting surface; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two poles configured to form an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly including a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of which are in contact with, or in close proximity to, the piece of high magnetic permeability material; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first pole thereof facing the annular peripheral surface of the wafer support; and the inner annular magnet ring having a polar axis parallel to the surfaces of the wafer support and having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing away from the central wafer supporting surface. 5. The apparatus of claim 4 wherein: the annular permanent magnet assembly has an intermediate magnet ring that has a polar axis parallel to the surfaces of the wafer support having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing toward the central wafer supporting surface. 6. A plasma processing apparatus comprising: a vacuum chamber; a wafer support within the chamber having a central wafer supporting surface and an annular peripheral surface surrounding the central wafer supporting surface; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two poles configured to form an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly including a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of which are in contact with, or in close proximity to, the piece of high magnetic permeability material; and the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support; the outer annular magnet ring having a first pole thereof facing the annular peripheral surface of the wafer support; and the annular permanent magnet assembly having an intermediate magnet ring that has a polar axis parallel to the surfaces of the wafer support having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing toward the central wafer supporting surface. 7. The apparatus of claim 6 wherein: the outer annular magnet ring has a polar axis perpendicular to the surfaces of the wafer support; and the inner annular magnet ring has a polar axis perpendicular to the surfaces of the wafer support and opposite to that of the outer annular magnet ring. 8. A plasma source comprising: a wafer support having an upwardly facing planar surface that includes a central wafer supporting surface and an annular peripheral surface surrounding the central wafer supporting surface; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the upwardly facing planar surface of the wafer support and having at least two annular magnetic poles, including an inner annular pole of a first polarity and an outer annular pole of the opposite polarity, configured to form a magnetic field over and parallel to the annular peripheral surface and perpendicular to the central wafer supporting surface that encloses the annular peripheral surface in a magnetic tunnel; the annular permanent magnet assembly including at least two annular magnet rings including an outer annular magnet ring and a second annular magnet ring located within the outer annular magnet ring, the rings each having north and south magnetic poles, the second magnet ring being either an inner annular magnet ring or an intermediate annular magnet ring located between the outer annular magnet ring and an inner annular magnet ring; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first role thereof facing the annular peripheral surface of the wafer support; and the second annular magnet ring having a polar axis parallel to the surfaces of the wafer support and having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing away from the central wafer supporting surface. 9. The source of claim 8 wherein: the annular permanent magnet assembly forms a magnetic tunnel that is operative to trap plasma forming electrons excited by the RF generator in the tunnel away from a wafer on the central wafer supporting surface to form a plasma that diffuses inward from the tunnel and over the surface of a wafer supported on the central wafer supporting surface. 10. The source of claim 8 wherein: the annular permanent magnet assembly includes a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of which are in contact with, or in close proximity to, the piece of high magnetic permeability material. 11. The source of claim 10 wherein: the outer annular magnet ring has a polar axis perpendicular to the surfaces of the wafer support. 12. The source of claim 10 wherein: the outer annular magnet ring has a polar axis perpendicular to the surfaces of the wafer support; and the inner annular magnet ring has a polar axis perpendicular to the surfaces of the wafer support and opposite to that of the outer annular magnet ring. 13. The source of claim 8 wherein: the annular permanent magnet assembly is configured to produce a magnetic field that is generally flat over at least a portion of the annular peripheral surface. 14. The apparatus of claim 8 wherein: the annular permanent magnet assembly is located behind the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly through and over the surfaces of the support. 15. The apparatus of claim 8 wherein: the annular permanent magnet assembly is located opposite and is spaced from the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly toward and through the surfaces of the support. 16. A plasma source comprising: a wafer support within the chamber having a central wafer supporting surface and an annular peripheral surface surrounding the central wafer supporting surface; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two poles configured to form an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly including a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of, which are in contact with, or in close proximity to, the piece of high magnetic permeability material; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first pole thereof facing the annular peripheral surface of the wafer support; and the inner annular magnet ring having a polar axis parallel to the surfaces of the wafer support and having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing away from the central wafer supporting surface. 17. The source of claim 16 wherein: the annular permanent magnet assembly has an intermediate magnet ring that has a polar axis parallel to the surfaces of the wafer support having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing toward the central wafer supporting surface. 18. A plasma source comprising: a wafer support within the chamber having a central wafer supporting surface and an annular peripheral surface surrounding the central wafer supporting surface; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two poles configured to form an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly including a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of which are in contact with, or in close proximity to, the piece of high magnetic permeability material; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first pole thereof facing the annular peripheral surface of the wafer support; and the annular permanent magnet assembly having an intermediate magnet ring that has a polar axis parallel to the surfaces of the wafer support having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing toward the central wafer supporting surface. 19. A plasma processing apparatus comprising: a vacuum chamber; a wafer support within the chamber having a central wafer supporting surface and a capacitively coupled plasma source that includes an annular peripheral surface surrounding the central wafer supporting surface that emits plasma forming electrons into the vacuum chamber; an RF generator coupled to the wafer support; and an annular permanent magnet assembly adjacent the annular peripheral surface of the wafer support and having at least two generally ring-shaped poles of opposite polarity configured to form a generally radial magnetic field enclosing an annular magnetic tunnel adjacent the annular peripheral surface and surrounding the central wafer supporting surface so as to trap plasma forming electrons emitted from the annular peripheral surface in the tunnel away from a wafer on the central wafer supporting surface such that a plasma formed in the tunnel diffuses inwardly from the tunnel and over the surface of a wafer supported on the central wafer supporting surface; the annular permanent magnet assembly including at least two annular magnet rings including an outer annular magnet ring and a second annular magnet ring located within the outer annular magnet ring, the rings each having north and south magnetic poles, the second magnet ring being either an inner annular magnet ring or an intermediate annular magnet ring located between the outer annular magnet ring and an inner annular magnet ring; the outer annular magnet ring having a polar axis perpendicular to the surfaces of the wafer support with a first pole thereof facing the annular peripheral surface of the wafer support; and the second annular magnet ring having a polar axis parallel to the surfaces of the wafer support and having a pole thereof that is of the same polarity as the first pole of the outer annular magnet ring facing away from the central wafer supporting surface. 20. The apparatus of claim 19 wherein: the annular permanent magnet assembly is located behind the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly through and over the surfaces of the support. 21. The apparatus of claim 19 wherein: the annular permanent magnet assembly is located opposite, and is spaced from, the annular peripheral surface of the wafer support and produces the magnetic tunnel with a magnetic field arcing from the poles of the assembly toward and through the surfaces of the support. 22. The apparatus of claim 19 wherein: the annular permanent magnet assembly includes a piece of high magnetic permeability material, an outer annular magnet ring and an inner annular magnet ring, the rings each having north and south magnetic poles, opposite ones of which are in contact with, or in close proximity to, the piece of high magnetic permeability material.